全文获取类型
收费全文 | 3242篇 |
免费 | 336篇 |
国内免费 | 820篇 |
专业分类
安全科学 | 702篇 |
废物处理 | 226篇 |
环保管理 | 411篇 |
综合类 | 2133篇 |
基础理论 | 255篇 |
环境理论 | 1篇 |
污染及防治 | 438篇 |
评价与监测 | 77篇 |
社会与环境 | 95篇 |
灾害及防治 | 60篇 |
出版年
2024年 | 10篇 |
2023年 | 43篇 |
2022年 | 80篇 |
2021年 | 122篇 |
2020年 | 109篇 |
2019年 | 111篇 |
2018年 | 99篇 |
2017年 | 118篇 |
2016年 | 140篇 |
2015年 | 150篇 |
2014年 | 199篇 |
2013年 | 223篇 |
2012年 | 295篇 |
2011年 | 298篇 |
2010年 | 236篇 |
2009年 | 220篇 |
2008年 | 182篇 |
2007年 | 290篇 |
2006年 | 264篇 |
2005年 | 182篇 |
2004年 | 159篇 |
2003年 | 136篇 |
2002年 | 124篇 |
2001年 | 109篇 |
2000年 | 103篇 |
1999年 | 86篇 |
1998年 | 70篇 |
1997年 | 55篇 |
1996年 | 39篇 |
1995年 | 35篇 |
1994年 | 21篇 |
1993年 | 16篇 |
1992年 | 26篇 |
1991年 | 9篇 |
1990年 | 8篇 |
1989年 | 4篇 |
1988年 | 4篇 |
1987年 | 2篇 |
1985年 | 4篇 |
1982年 | 3篇 |
1979年 | 3篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1974年 | 5篇 |
1971年 | 2篇 |
排序方式: 共有4398条查询结果,搜索用时 87 毫秒
721.
气体悬浮吸收干法脱硫工艺 总被引:1,自引:1,他引:0
论述气体悬浮吸收(GSA)干法脱硫工艺过程、原理及特点,对该工艺在国内外实际工程中的应用作了介绍。 相似文献
722.
PCDDs/DF and Co-PCB (dioxin) formations were studied with ash from a newly developed gasification and melting process for
municipal solid waste. Ash samples were heated in a laboratory-scale fixed-bed reactor. Emphasis was placed on the effects
of the type and composition of ash, temperatures, gas residence time, and gaseous organic precursors. Investigations using
macroscopic and homologue distribution analyses led to the following conclusion. The ash from the gasification–melting process
had the ability to generate dioxins in flue gas. A possible carbon source is unburned carbon in the ash samples, although
this was very low (less than 0.01%). An experimental result that the level of dioxins generated from preheated fly ash obtained
from a conventional incinerator was much lower than that from nonheated fly ash supported this conclusion. Dioxin concentrations
obviously showed temperature dependence and peaked at 350°C. Dioxins formed in a gasification–melting process ash were readily
desorbed from the surface, probably because of the low carbon content of the ash. There was no experimental evidence that
gaseous organic precursors fed to the reactor generated dioxins. Therefore, an organic precursor was not essential for the
formation of dioxins. A good linear relationship obtained between PCDDs/DFs and gas residence time also supported the assumption.
Received: February 14, 2000 / Accepted: June 30, 2000 相似文献
723.
724.
725.
726.
727.
介绍了极板转运装置自动控制系统的设计思想.详细阐述了系统的组成,检测开关的现场布置以及系统程序的设计. 相似文献
728.
对煤矿安全量化管理方法进行了理论上的深化和手段上的完善,提出了利用层次分析法确定安全管理目标标准分的方法,研制了实用、有效的应用软件系统。 相似文献
729.
730.
Andrew O. Finley Sudipto Banerjee Ronald E. McRoberts 《Environmental and Ecological Statistics》2008,15(2):241-258
In efforts such as land use change monitoring, carbon budgeting, and forecasting ecological conditions and timber supply,
there is increasing demand for regional and national data layers depicting forest cover. These data layers must permit small
area estimates of forest area and, most importantly, provide associated error estimates. This paper presents a model-based
approach for coupling mid-resolution satellite imagery with plot-based forest inventory data to produce estimates of probability
of forest and associated error at the pixel-level. The proposed Bayesian hierarchical model provides access to each pixel’s
posterior predictive distribution allowing for a highly flexible analysis of pixel and multi-pixel areas of interest. The
paper presents a trial using multiple dates of Landsat imagery and USDA Forest Service Forest Inventory and Analysis plot
data. The results describe the spatial dependence structure within the trial site, provide pixel and multi-pixel summaries
of probability of forest land use, and explore discretization schemes of the posterior predictive distributions to forest
and non-forest classes. Model prediction results of a holdout set analysis suggest the proposed model provides high classification
accuracy, 88%, for the trial site.
相似文献
Ronald E. McRobertsEmail: |